Respirometer



w. E. GILSQN 3,313,115?

RESPIROMETER 4 Sheets-Sheet 5 April 11, 1967 Filed March 27, 1964 April 11, 1967 w. E. GILSON RESPIROMETER 4 Sheets-Sheet Filed March 27, 1964 Wham; flaommw, yaw 140M4 4 MA 147'7'0KA/EYS.

United States Patent 3,313,157 RESPROMETER Warren E. Gilson, Madison, Wis. Gilson Medical Electronics, 3000 W. Beltline, Middleton, Wis. 53562) Filed Mar. 27, 1964, Ser. No. 355,158 12 Claims. (Ci. 734fl1) The present invention relates to respirometers and has for its primary object the provision of a new and improved differential respirometer system.

The use of differential manometers for respiratory studies has been advantageous, as the influence of varying barometric pressure may thereby be eliminated. Differential manometers, however, have been little employed because of their complexity, fragility, and cumbersome size. One difiiculty has been the necessity of balancing each flask with a reference flask thereby cutting in half the measurements that can be made at one time. Constant pressure systems have also been used in respirometers for many years. The change in volume is compensated for by the measured movement of a plunger in the enclosed space. There is no change in the level of the manometer fluid.

The present invention provides a constant pressure differential manometer system utilizing a single reference flask and a plurality of active flasks. The eflect of varying barometric pressures and variations in temperature are eliminated. In addition, with an attached barometer and a system for evacuation and supplying gas, an experiment can be conducted at standard pressure or other pressures in order to simplify calculations and in different atmospheres.

An object of the present invention is the provision of a new and improved differential respirometer system including a plurality of active flasks and but a single reference flask balancing the said plurality of flasks against changes in barometric pressure and temperature. The system is such that when combined with a constant pressure the system provides an increase in accuracy and repeatability of about five times that of standard Warburg apparatus without the added bulk or complexity of multiple reference flasks.

A further object of the present invention is to provide a system as aforesaid with improved valving arrangements enabling simpler as well as different types of operations.

A further object of the present invention is to provide a respirometer system including a number of flasks with associated valves in which the valves may be operated either simultaneously or individually, as desired.

A further object of the present invention is to provide a new and improved valve adapted especially for a respirometer system.

Another object of the the present invention is the provision of a new and improved support for the manifold used with the apparatus.

A further object is the provision of a manometer with a new and improved movable cursor with an index there- Another object is the provision of a new and improved respirometer comprising a novel flask support and means movably supporting the former in different positions within and outside a container.

In brief, the differential respirometer and system of the present invention includes a container adapted to contain a liquid bath into which both active and reference "ice flasks may be placed. The flasks are constructed as slidable sub-assemblies and carriers for the slides are provided inside of and at the front of the container. The slides and carriers are so constructed that the flasks may be located at high and low positions on the carriers both inside and outside of the container. The slides are all mounted on a shaker mechanism so that the flasks may be shaken during the experiment. All the flasks are connected to a common manifold whereby there is required but a single reference flask for the many active flasks. Each of the active flasks has associated with it a differential manometer. The manometers are supported in visible aligned relation above and to the rear of the container upon suitable vertical supports. The manometers have individually operable shut off valves whereby they may be disconnected from the manifold. They also have valves between the manometer legs which can be opened for equalization of pressures in the manometer legs and for pressure equilibration by connection of the flask side legs momentarily to the atmosphere. These valves are provided with handles and the apparatus is provided with a pair of handle operating means whereby the valves may be all closed simultaneously or opened simultaneously. The valves may also be individually operated. The valves are also of a simple and effective construction including plug elements sealed at opposite ends with plug encircling O-rings. Sealing of the junction of passageways and the valve plug is provided by arcuately compressed O-rings.

Other objects and advantages of the present invention will become apparent from the ensuing description of an illustrative embodiment in the course of which reference is had to the accompanying drawings, in which:

FIG. 1 is a diagrammatic representation of a difi'erential respirometer system constructed in accordance with the present invention;

FIG. 2 is a fragmentary and partly broken away front view of the differential respirometer;

FIG. 3 is an enlarged fragmentary vertical cross sectional view taken along the line 3-3 of FIG. 2 and illustrating the manometer with its associated valves in their closed positions;

FIG. 4 is a further enlarged fragmentary view taken along the line 4-4 of FIG. 2 and illustrating additional details of a manometer;

FIG. 5 is a vertical cross sectional view taken along the line 5-5 of FIG. 4 and illustrating details of construction of a valve;

FIG. 6 is a fragmentary elevational View taken along the line 66 of FIG. 4 and illustrating a movable cursor forming part of a manometer;

FIG. 7 is an exploded view illustrating details of construction of the valves embodied in the apparatus;

FIG. 8 is a fragmentary vertical cross sectional view taken along the line 88 of FIG. 2, illustrating in solid lines a flask and associated support with the flask immersed in the bath and illustrating in phantom the flask in a position corresponding to the first but elevated above the container and illustrating in a further phantom position the flask support in front of the apparatus;

FIG. 9 is a horizontal cross sectional view taken along the broken line 99 of FIG. 8; and

FIG. 10 is a similar view taken along the line 10--10 of FIG. 8.

Referring now to the drawings and first to FIG. 1, the system of the present invention is there shown quite diagrammatically. The system, indicated as a Whole by reference character 10, includes a plurality of active flasks 12 and a single reference flask 14 all supported in a liquid bath 16 below the level of the liquid which is indicated by reference character 18. The reference flask 14 is connected, as by flexible tubing 19, to a manifold 20 provided with a valve 22 at its end whereby the manifold may be connected to atmosphere or evacuating means, or a source of gas, not shown, through a conduit 24.

The system includes also a plurality of differential manometers all of identical construction and only one of which will be described. Each manometer includes two legs 32 and 34 of which the latter is connected to an active flask through conduit 36 which may be of or include flexible tubing or the like and a combined tube and stopper 38. The interconnected lower ends of the arms 32 and 34 are provided with manometer fluid 40 and the legs are provided with index marks 36 (only one leg may have associated with it such a mark on a movable cursor, as will be described in greater detail hereinafter).

A shut off valve 42 of a novel construction, to be described hereinafter, is provided between the two legs of the manometer at the level of the end of tube 36 leading to manometer leg 34. This valve may be opened or closed and performs the two functions necessary for an experiment which requires gassing. The functions are: (1) to provide a connection between the two legs of the manometer to equalize pressure and (2) momentarily to connect the flask side of the manometer to atmosphere for pressure equilibration. Generally the valve is closed. The upper end of manometer leg 32 is provided with a shut off valve 44, which is like the valve 42, for the purpose of enabling individual disconnection of the manometer from the manifold 20. The upper end of manometer leg 32 beyond the valve 44 is connected to the manifold as by a short piece of tubing 46.

Considerable simplification in use of the equipment is provided by a volumetric micrometer 50 at the upper leg of arm 34 which is utilized to return the manometer fluid to a balanced condition by movement of a piston in the enclosed volume. The micrometer is calibrated to read directly in microliters thereby considerably simplifying calculations.

In operation of the system of FIG. 1, all the valves 44 are opened. These valves are generally left open all the time and are seldom used. Actually they are used only to disconnect a flask-manometer combination if it is not to be used in an experiment. The valve 22 likewise is open to connect the manifold to atmosphere or to some other gas should such be used. The valves 42 are also open. The reference flask 14 contains the same solution, usually plain water, as is used in the active flasks 12. A respiring material to be tested is placed in the active flasks and during a test this material generally consumes oxygen from the air. The micrometer 50 is adjusted to some convenient reading, say 200 microliters.

In performance of a test, all the valves 42 are closed and as will be described hereinafter this is accomplished advantageously by means of a single valve operating handle. During the test the respiring material absorbs the oxygen with the result that the liquid in the leg 34 connected to the active flask rises and that in the other leg falls. During the experiment readings are obtained at suitable time intervals by operating the micrometer 50 to bring the liquid in the manometer legs into balance. The readings are direct readings in microliters so that the readings are obtained simply and quickly.

The advantages of the system are freedom from varying barometric pressures or changing temperatures in the water bath. The manometers and volumetric micrometers are also visible at all times. Also, great convenience is afforded in changing the gases that may be used and other advantages result from the equipment to be described.

The detailed construction of the apparatus will now be described. In this description the reference characters utilized in FIG. 1 will be applied to the apparatus as far as possible. Parts of the apparatus not important to the present invention have not been illustrated in detail.

Referring first to FIGS. 2 and 8, the apparatus includes a base 60 shown only fragmentarily. Supported on the base is a container 62 for the liquid bath 16, which is shown rising to a level 18 and in which the flasks are immersed in use. Two of the flasks are shown in FIG. 2. For purposes of description it will be assumed that the flask shown at the left in FIG. 2 is an active flask 12 and the one shown at the center is the reference flask 14. These flasks are shown supported within the container 62 and they would be immersed in the bath, which is generally maintained at a predetermined temperature.

The flasks are supported on a mechanism adapted continuously to be oscillated thereby to shake the flasks with their contents. This mechanism is indicated by the reference character 64 and it comprises a cross arm 66 extending over the top of the container 62 and a pair of upstanding arms 68 at the opposite ends of and outside of the container. The arms 68 are pivotally mounted and pivotally related to the cross bar 64. Also, they may be oscillated by a motor or the like in a manner not shown.

in the illustrated embodiment provision is made for a reference flask and four active flasks. The individual flasks are detachably mounted on downwardly extending channel type supports or carriers 79 constituting vertically disposed slideways with detent apertures 72 and 74 utilized in holding the flask assemblies in the bath or removed from and above the bath. The supports 70 are secured at their upper ends to the cross arm 66 as by screws 76.

The flask assemblies are best illustrated in FIGS. 8, 9 and 10. A flask assembly includes a channel type slide nested and slidably received in the supports 70 so that the slide 80 may readily be moved up and down in and removed from the supports 70. The slide 80 is adapted to be held in two positions on the carrier 70 by an elongated and generally triangularly shaped latch or detent arm 82 having a short detent finger 84 at its lower end. In the solid line position illustrated in FIG. 8, the detent finger 84 is located in the lower aperture 72 thereby holding the slide 80 in its lower position with the flask 14 immersed in the liquid bath 16. In the dotted line position, the flask 14 is lifted above the container 62, thereby making the flask easily available for inspection or change, etc. In this upper position the detent finger 84 projects into the aperture 74.

The detent arm 82 is pivotally supported on the slide by a pivot bolt 86 passing through a bushing 88 and a pair of opposed tube supporting brackets 90 having arcuate end portions 92 encircling the combined tube and stopper 38. The upper vertical part of member 38 is releasably secured in the brackets 90, being releasable upon loosening of the screw bolt 94. Member 38 has a horizontal portion 33A that is held between opposed arcuate bracket portions 92A, the better to hold it in oriented position. As illustrated, the flask is held in assembled relation relative to the tube and stopper by a pair of springs 96. The springs are releasable from both the flask and the tube so that the flask may be readily detached as desired.

The detent arm 82 is biased into position to engage the bottom of the carrier 70 so that the detent finger 84 will readily slide into either aperture 72 or 74 as the slide is moved in the carrier. This biasing is effected by a leaf spring 98 secured to the forward part of arm 82 and having a rounded portion 98A engaging the slide. The slide is provided with an upstanding bent finger 100 and the detent arm with a forwardly bent finger 102 at the level of the finger so that the detent may be easily operated to release the assembly.

The horizontal portion 38A of the combined tube and stopper 38 is adapted to be connected by a length of flexible tubing corresponding to tubing 36 of a length sufficient to enable the flask assembly to be moved to the upper phantom position and, in accordance with another feature of the invention, to a position in front of the container 62, where it can be supported on a carrier 70A in all respects like the carrier 74 but secured to the front of the cabinet upon a crosspiece 104. Accordingly, the flask assembly can be secured at the front of the cabinet in either a low or high position depending on whether or not the detent finger 84 is in the upper aperture 74A or the lower one 72A.

The manometers and volumetric micrometers are supported above and to the rear of the container 62 upon a pair of spaced apart uprights suitably secured to the base 60. The spaced supports are interconnected at their upper rear ends by a crosspiece 112 forming also a support for the micrometers, the latter being secured thereto by screws 114, see particularly FIGS. 2 and 3. The end supports 110 are additionally interconnected by a lower crosspiece 116 and an intermediate :one 118 which is also spaced back from the former and which provides a two point support for the manometers, the latter being secured thereto by the screws 120 and 122, see particularly FIG. 3.

A pair of rods 124 and 125 also extend between the spaced uprights 110. These are utilized for guidance of the flexible tubing 36 heretofore referred to as connecting the flasks to the manometers which tubing may be maintained taut by suitable tube retracting mechanism, not shown. A series of spools 128, only one of which is shown, may be placed on the rods for guidance of the tubing.

The volumetric micrometer 50 includes a body and a rotatable and axially movable adjusting element 132 to the lower end of which is attached a piston 134, see FIG. 4, adjustably closing the upper end of the manometer leg 34 which is connected by the tubing 36 to the reference flask. The micrometer 50 is constructed and arranged to provide digital readings directly in microliters in a range from 0 to 500. The digital reading for 200 microliters is illustrated on the micrometer on the extreme left of FIG. 2, the digits being on the three rotating discs 136.

The micrometer is detachably secured to the upper end of manometer leg 34 by a coupling element 138. Referring to FIG. 4 the coupling engages a split bushing at its lower end and, likewise, engages a sealing washer 142 between the body and upper end of manometer leg 34. An O-ring 144 is provided to provide sealing around the piston 134.

The manifold 28, which has a longitudinal passageway 20A therein, is also supported by the manometers between the crosspieces 110, as by short pieces of flexible tubing 146. One end of the manifold may also be supported in a manner not shown by one of the uprights 110 and this end may have attached to it the valve 22 referred to in connection with FIG. 1.

A movable cursor 150, illustrated in FIGS. 4 and 6, is slidably mounted between the manometer legs 32 and 34. It is of telescopic construction including an outer portion 152 and an inner portion 154 that are biased apart by a spring 156 so that the outer ends of the portions movably abut against the legs 32 and 34. The portion 154 is provided with an index line 158 which is normally at a point at which the height of the liquid in both legs is the same and which can be seen through the transparent material of which the manometer is made.

The valves 42 and 44 are the same in construction and only one will be described while like parts are indicated by like reference characters.

Each valve includes a body 160 having a transverse recess 162 rotatably receiving a cylindrical plug valve element 164 having a transverse passageway 166 through it.

Referring particularly to FIGS. 5 and 7, it will be noted that the body is provided with counterbores 168 at its opposite ends for the reception of O-riugs 170 providing sealing around the plug. One of the O-rings is held in compression by a collar 172 secured to a projecting end of the plug as by a set screw 174. The opposite end of the plug is held in assembled relation by the valve operating handle or rod 176 between which and the body there is located a washer 178. The handle is movable from its solid line closed position, determined by stop 177A, to a dotted line open position, determined by stop 177B. The passageways in the valve body leading to the plug at the interior of the valve are provided with counterbores 180 of arcuate nature to receive O-rings 182 and to confine them in arcuate relationship to the exterior of the valve body thereby to seal the passageways controlled by the valve body.

The manometers are all supported in a horizontal line and so as to be visible at all times. Also, in accordance with the present invention, the valves 42 controlling communication between the legs of the manometer are arranged and constructed so as to be openable or closable simultaneously as Well as individually. These valves are each provided with a somewhat elongated handle 184 by means of which the valves may be individually operated. Referring to FIG. 3, the handle 184 is shown in solid line in the position it occupies when the valve is closed While the open position is shown in phantom.

Simultaneous movement of all of the valves to their dotted line open positions can be effected by movement of a handle operator indicated as a whole by the reference character 186. The latter is mounted at the outer ends of arms 187 secured to a rotatable shaft 188, the opposite ends of which are received in the end supports 110. The outer ends of lever 187 of the handle operator are connected by transverse rod 190 which is engageable with all of the handles 184. Consequently, when the operator 186 is moved from its solid line to its dotted line position, as shown in FIG. 3, the valve is opened. The closed position of a valve is determined by a stop 192 and the open position by a stop 194. To facilitate movement of operator 186 there are provided a pair of forwardly extending operating levers 196 which are secured to the levers 187. It should be noted that the levers 196 are located, as are the levers 187, at the inner sides of the support 110.

Simultaneous movement of the valves 42 from their dotted line open position to the solid line closed position is effected by a second handle operator 198. It includes a transverse rod 200 mounted at the free ends of levers 202 mounted on a rotatable cross shaft 204 mounted upon the supports 110. Operating levers 206 are attached to the levers 202 so that the operator may readily manipulate the handle operator. These levers are mounted at the outer sides of the end supports 110.

Both handle operators 186 and 198 are biased to their indicated upper positions by springs. The spring for operator 186 is indicated by reference character 288 and that for operator 198 by 210. The up position of handle 184 is determined by opposed stop pins 212 projecting a short distance inwardly from each end support 110.

The manometers and the volumetric micrometers are preferably made by injection molding of some suitable plastic material, such as Lexan. Accordingly, they may be made and assembled quite readily in an apparatus such as shown.

The use of the system as a whole has already been described. A brief review will now be made of the use of the specifically described construction of the apparatus. At the start of an experiment the flask slides 80 are moved into their upper positions above the container 62 or to the front of the container, as illustrated in FIG. 8. Thereafter the material to be placed under test is placed into the active flasks 12 and the reference flask is supplied with a solution corresponding to that used in that of the active flasks. It may be noted that the flasks are 7 easily detached from or mounted upon the combined tubes and stoppers 38 mounted upon the slides 89. To place the slides and flasks in the liquid bath in the container, the finger pieces 100 and 162 may be grasped thereby to operate the detent arm 82 to release the detent 84, for example from the aperture 74. Thereafter the slides 80 may be lowered in the carrier 70 until the latch 84 goes into the aperture 72, which it does under the influence of leaf spring 78.

As previously indicated, the shut off valves 44 are normally open. In order to balance the pressures in the manometer legs the valves 42 are all opened by movement of handle operator 186 by means of its lever 196. This at the same time not only balances the pressures in the manometer legs but also equalizes the pressures in the system as a result of connection thereof to the manifold, which is open to atmosphere, or some other gas or pressure source.

Thereafter the valves 42 are all closed by operation of handle operator 198 through its operating lever 206.

Assuming that the micrometer had been set at 200 microliters to provide equal heights of liquid in manometer legs 32 and 34, then during the experiment readings may be taken by adjustment of the micrometer to bring the level of the liquid in the manometer legs back to the same height, which may be readily determined by use of the cursor 150 and its index 158. As previously indicated, the micrometer is calibrated in microliters so that the readings can be taken quickly and simply.

After the experiment is over the flask assemblies and carriers 80 may be lifted to a position above the container or, if desired, they may be removed entirely from within the container and attached to the supports 70A in front of the container.

While the present invention has been described in connection with details of an illustrative embodiment thereof it should be understood that such details are not intended to be limitative of the invention except insofar as set forth in the accompanying claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicat ing with a respective one of said active flasks and a second leg communicating with said manifold, and a single reference flask communicating with said manifold and through it with the second legs of the manometers.

2. A differential respirometer as claimed in claim 1, wherein the respirometer is of the constant pressure type and including a plurality of digital reading volumetric micrometers, each communicating with a first leg of an associated manometer.

3. A differential respirometer as claimed in claim 1, in which the manifold is of one piece construction and including means connecting said manifold to and supporting it upon a single leg of each of said manometers.

4. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, a single reference flask communicating with said manifold and through it with the second legs of the manometers, and a container adapted to contain a liquid in which said flasks are disposed.

5. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, a single reference flask communicating with said manifold and through it with the second legs of the manometers, a container for a liquid, and means movably supporting said active flasks in said container in a first position in which the flasks are immersed in the liquid and a second position above the liquid.

6. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, a single reference flask communicating with said manifold and through it with the second legs of the manometers, and means including valve means and a passageway between the legs for controlling communication between the legs and adapted to be opened to equalize pressures in the legs and to be closed during use of the respirometer.

7. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, 21 single reference flask communicating with said manifold and through it with the second legs of the manometers, means including valve means and a passageway between the legs for controlling communication between the legs and adapted to be opened to equalize pressures in the legs and to be closed during use of the respirometer, and shut off valve means between the second legs and manifold for effectively disconnecting the manometers from the manifold.

8. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, a single reference flask communicating with said manifold and through it with the second legs of the manometers, each manometer having a passageway between its legs and a valve operable to open or close the said passageway, an operating handle for individual operation of each valve, and manually operable means for simultaneously opening and simultaneously closing all said valves.

9. A differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks and a second leg communicating with said manifold, a single reference flask communicating with said manifold and through it with the second legs of the manometers, each manometer having a passageway between its legs and a valve operable to control said passageway, an operating handle for each valve, and manually operable means for simultaneously operating all said valves.

10. A differential respirometer including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each having one leg communicating with a respective one of said active flasks, a single reference flask communicating with said manifold and through it with the second legs of the manometers, an assembly for holding at least one of said flasks including a slide, means on the slide for supporting said flask and movably mounted detent means on said slide for supporting said flask in different positions.

11. A differential respirometer including in combination a plurality of active flasks, a manifold, a plurality of differential manometers, each having one leg communicating with a respective one of said active flasks and a second leg substantially parallel thereto, a single reference flask communicating with said manifold and through it with the second legs of said manometers, and a cursor mounted between the respective legs of one of said manometers for movement therebetween, said cursor including telescopically arranged portions, each engaging a leg and spring means biasing said portions against said legs.

12. A constant pressure type differential respirometer, including in combination a plurality of active flasks, a manifold, a plurality of differential manometers each References Cited by the Examiner UNITED STATES PATENTS 1,775,227 9/1930 Riggs 73-401X 1 0 2,026,842 1/1936 Matuszak 23254 3,023,622 3/ 1962 Hezarifend 73401 3,108,779 10/1963 Anderson 251309 3,199,835 8/ 1965 Freed 251309 OTHER REFERENCES Umbriet et al., Manometric Techniques, Minneapolis, Minn, Burgess Publishing Co., 1957. Pages 70, 71, 79 and 80.

LOUIS R. PRINCE, Primary Examiner.

D. O. WOODIEL, Assistant Examiner. 

1. A DIFFERENTIAL RESPIROMETER, INCLUDING IN COMBINATION A PLURALITY OF ACTIVE FLASKS, A MANIFOLD, A PLURALITY OF DIFFERENTIAL MANOMETERS EACH HAVING ONE LEG COMMUNICATING WITH A RESPECTIVE ONE OF SAID ACTIVE FLASKS AND A SECOND LEG COMMUNICATING WITH SAID MANIFOLD, AND A SINGLE REFERENCE FLASK COMMUNICATING WITH SAID MANIFOLD AND THROUGH IT WITH THE SECOND LEGS OF THE MANOMETERS. 